ASVAB Mechanical Comprehension Practice Test 342489 Results

Your Results Global Average
Questions 5 5
Correct 0 3.49
Score 0% 70%

Review

1

The steering wheel of a car is an example of which type of simple machine?

89% Answer Correctly

first-class lever

wheel and axle

fixed pulley

block and tackle


Solution

A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.


2

Which of the following is not a type of bridge?

74% Answer Correctly

block

truss

arch

cable


Solution

The six basic bridge forms are beam, truss, arch, cantilever, cable, and suspension.


3

Drag is a type of:

82% Answer Correctly

kinetic energy

friction

potential energy

work


Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.


4

The advantage of using a third-class lever is that it increases:

37% Answer Correctly

the speed of the load

the mechanical advantage of the lever

the distance traveled by the load

the force applied to the load


Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.


5 What is the efficiency of a machine has work input of 220 ft⋅lb and work output of 77 ft⋅lb?
67% Answer Correctly
0%
35%
8%
140%

Solution
Due to friction, a machine will never be able to utilize 100% of its work input. A certain percentage of that input will be lost in overcoming friction within the machine. Effeciency is a measure of how much of a machine's work input can be turned into useful work output and is calculated by dividing work output by work input and multiplying the result by 100:
\( Efficiency = \frac{Work_{out}}{Work_{in}} \times 100 \) \( = \frac{77 ft⋅lb}{220 ft⋅lb} \times 100 \) \( = 35% \) %